This invention relates to electronic musical synthesizers and more particularly relates to improved circuitry for recalling, editing and restoring parameter signals representing different timbres of sound.
Electronic musical synthesizers are valued by musicians for their ability to create different qualities or timbres of sound. Whereas a piano or trumpet can create only a single characteristic timbre of sound and an organ can create at most a few dozen different timbres of sound, a typical synthesizer can create thousands of different timbres. In this specification and claims, timbre means the quality or characteristic of a sound. The quality or character may be controlled by various sound parameters, such as, for example, frequency, octave, waveshape or harmonic spectrum.
Electronic musical synthesizers have been reduced in size and cost dramatically over the past decade. As a result, they are being used in live performances to a greater extent than ever before. This use of synthesizers has created a need for improved means of conveniently and accurately altering the vast number of different sound timbres which a synthesizer can create.
In order to generate a specific sound on a typical synthesizer, the performer must carefully set the position of many control knobs. There may be 40 to 100 such control knobs that require individual manipulation in order to achieve the desired timbre of sound. During a live performance, the performer may want to change the timbre of the sound from one section of a composition to another. Typically, such a transition must be achieved in less than one second. The transition cannot be made if a large number of control knobs must be repositioned.
In order to overcome the foregoing limitation of synthesizers, there have been attempts to fabricate programming circuits capable of storing the positions of the control knobs and automatically recalling the stored information in order to produce a desired timbre of sound. One such programming circuit is described by Thomas E. Oberheim published in Preprint No. 1172 (E3) entitled "A Programmer for Voltage-Controlled Synthesizers" which was presented to the Audio Engineering Society at its 55th convention Oct. 29-Nov. 1, 1976. Although the Oberheim programming circuit provides a means of rapidly changing from one prestored timbre of sound to another, it does not provide any means of "editing" the stored information. In order to change the information stored by the Oberheim circuity, each of the synthesizer control knobs and settings must be properly positioned from "scratch". That is, each of the control knobs must be set or repositioned even if only one of the control knobs needs to be altered in order to edit the stored information to create the desired timbre. As a result, it requires a relatively long period of time in order to edit or modify a stored timbre of sound. This limitation has prevented synthesizers from realizing their full potential, especially as performing instruments.
Accordingly, it is one object of the present invention to develop an electronic musical synthesizer capable of conveniently editing a preset group of parameter signals representing a predetermined timbre of sound which has been stored in a memory.
Another object of the invention is to produce a synthesizer of the foregoing type in which an indicator informs a performer when a control knob of the synthesizer has been reset to the same position previously used to store a signal in the memory.
Still another object of the invention is to produce a synthesizer with an indicator of the foregoing type in which the indicator shows a performer when the setting of the control knob is above or below the value stored in memory.
Another object of the invention is to provide a multiple edit synthesizer in which all of the control knobs are simultaneously available to modify a stored sound timbre, so that the performer can change the knobs in any order and instantaneously hear the resulting changes in sound timbre.
Yet another object of the invention is to provide a synthesizer in which an edited timbre of sound can be directly compared with an originally-stored timbre of sound.
Still another object of the invention is to provide a synthesizer which can be controlled either from information stored in memory or from local control knobs.
Yet another object of the invention is to produce a synthesizer with an editing feature which enables certain parameter circuits of the synthesizer to be controlled from memory and other parameter circuits of the synthesizer to be simultaneously controlled from a control knob.
Still another object of the invention is to provide a synthesizer of the foregoing type in which an edited version of a previously stored group of parameter signals is temporarily held in an auxiliary memory, and the synthesizer can be controlled from the auxiliary memory.
Yet another object of the invention is to provide a single edit synthesizer in which a single indicator can be used to show a performer whether any one of a plurality of control knobs is in the position previously used to store information in memory.
Still another object of the invention is to provide a single edit synthesizer in which multiple control settings can be recalled and edited using a single digital-to-analog converter and a single analog-to-digital converter.